murphy



Feb. 7, 1956 T. J. MURPHY 2,734,139

ELECTRICALLY OPERATED ERASER AND SIMILAR DEVICES Filed April 2'7, 1951 2 Sheets-Sheet l s 5/ t r 47 73 a 19 I w 64 A 49 6 69 [Z I j j '3 23 55 fir/ 7.5 31mentor %4AZZfi W Qtt nmus ELECTRICALLY OPERATED ERASER AND SIMILAR DEVICES Filed April 27, 1951 T. J. MURPHY Feb. 7, 1956 2 Sheets-Sheet 2 %W 3m entor 69 y United States Patent ELECTRICALLY OPERATED ERASER AND SIMILAR DEVICES Thomas J. Murphy, Stamford, Conn.; Mary Louise Murphy, Stamford, Conn., executrix of said Thomas J. Murphy, deceased Application April 27, 1951, Serial No. 223,194

Claims. (Cl. 310-29) This invention relates to an electrically operated device, such, for example, as an electrically operated tool, and while it is shown as operating an eraser, it will be understood this is shown by way of example and it may he used for operating other tools, such, for example, as a burnishing tool, electric shavers, or similar devices.

has for an object to provide a construction and arrangement in which pressure on'the tool in use controls the operation of the'tool.

Another object is to provide a construction in which when pressure on the tool is released the activator will automatically cease functioning.

Another object is to provide an improved activator comprising electric coils which are so wound as to reduce arcni at the control switch toa minimum.

with the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawin {orming a part of this specification. It is, however, to be understood the invention is not limited to the specific detai s of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In these drawings:

Fig. 1 is a longitudinal section through the casing of the device on an enlarged scale and showing most of the operative elements in side elevation;

llig. 2 is a similar section on a plane at substantially right angles :to Fig. l and showing certain of the parts in elevation;

Fig. 3 is a side view ,of .the head end of the device showing it in operation and with part of the casing broken away to show part ofwthe control switch;

4 .is a transverse section substantially on line 3-4 of Figs. 2' and 3;

Fig. 5 is a partial side elevation and partial section of the drive from the armature to the tool;

Fig. 6 is a side elevation and partial diagrammatic view of the core and exciting coils of the activator, and

Fig. '7 is a wiring diagram for the coils of the activator.

As suggested above, the device is-shown as operating an eraser or similar reciprocating device, but it will be understood :it may be used :for operating other reciproeating tools, such, .for example as aburnisher, dry shavers, and other tonsorial devices, or similar devices. It comprises a casing or housing '10 made of any suitable ma terial, such, for example, aseither metal or molded plastic, and this casin ismade in two sections 11 and 12 joined at substantially a midpoint by a step joint 13. Within this casing .or housingis enclosed an activator or electric motor 124, the lead connections 15 from .a source of our rent to this activator or .motor,.zand the .drive mechanism from .this activator to thetool, in this case shown as an eraser 16 or" suitable erasing material, such, for example, as gritty rubber composition, for erasing ink, pencil, or other lines .orrnarks.

The motor or activator comprises a laminated core 17 formed .of .a series of ilaminationsof .relatively .thin

No. 2,434,671, grante .lanuaryizo, 1948.

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intermediate leg 19 connected at one end 20, and thus providing spaced magnetic poles 21 and 22 at their free ends. Any desired number of laminations may be used, arranged in superimposed relation side by side and bound together by any suitable means, such, for example, as transverse rivets 23 and 24. This core is magnetized or excited for operation of the armature 25 located adjacent the free ends of the poles 21 and 22 by the coils 26, 27, 2?; and 29 connected as indicated in Fig. 7 and wound around the center leg 19 of the laminated core. Two coils 26 and 27 are the main exciting coils and are wound together and at the same time in the same direction with the turns of the two coils side by side and parlei to each other, and they are connected so that the two coils are complementary to each other and therefore are not opposed. In this arrangement one end of the coil 26 is connected'to one side 30 of the source of current supply 31, such as an A. C. source of current, and the other side 32 is connected to the opposite end of the coil 27. Thus, as shown in Fig. 7, in the particular arrangement illustrated the lead 30 from one'side of the source of current is connected to the'upper end of the coil 26 and the other side 32 is connected to the'lower end of coil 27. The lower end of coil 26 is connected by lead 33 and control switch 34 to the lead 35 connected to the upper end of the coil 27, and therefore, th'e'two coils 26 and 27 are connected in series, but are not connested together at the same ends so they are magnetically complementary to each otherand do not oppose each other, thus giving maxi-mum potential between all turns. The effect is really a distributed capacity, and the two coils wound and connected as shown produce a capacitative winding. In the connections 33, 315 betweenthe two coil are potential absorbing coils 2-8 and 29 of comparatively few turns. These auxiliary coils absorb the high tension at the break to lower the tension in the main coils to normal when the circuit is opened, therefore preventing breakdown between the turns of the main coils. There are a relatively large number'of turns in'the main coils 26 and 27, in .the arrangement shown approximately 3000 in each, :but a relatively few number of turns are required in the coils 28 and 29, approximately twentyfive being all that is necessary in the device shown, although -a greater or less number willfunction, and it will be understood the number of turns in the various coils may be varied as found necessary or desirable for the device to be operated. The inductive turns of the coils 23 and 29 may be wound over the main coils or separate from them. That is, these coils 28 and 29 absorb the high tension at the break to lower the tension in the coils .to normal. It makes no difference in which direction the coils 28 and 29 are wound and it is preferred that the adjacent turns :be spaced from each other to prevent breakdown from high tension. In some uses or installations the auxiliary coils may be used at beginning and ends of main coils. Furthermore, in some uses or installations, the leads 30 and 32 may be connected or closed while the current supply lines are connected to the free terminals (that is, in place of switch 34) of the inductive turns or coils 28 and 29.

The armature 25, as shown in Figs. 1, 5 and 6, is located closely adjacent the free ends of the core poles 21 and 22 and comprises two spaced inductively magnetized poles 36 separated by an air gap 37, vbut magneticallyconnected by the bar 38 over ,the gap. The core 13 arranged as shown really forms two separate magnetic circuits, one being formed by the left hand leg 18 .and center leg 19, andthc other by ,the right hand leg 18 and the center leg 19, and themfore as the armature 25 .re-

.ciprocates, the poles 3.6 pass alternately from one magneticcircuitto the other, as disclosed in my prior-Patent This armature is supported by a pair of flat springs 39 connected at their lower ends to the opposite ends of the armature by the angular shaped yokes 4-0, the upper horizontal leg 41 resting on top of the armature and secured thereto by any suitable means as the screws 42 and the upright legs 43 being placed against the ends of the armature and being secured thereto by suitable screws or rivets 44, these latter fasteners also securing the lower ends of the springs to these yokes. These springs tend to return the armature to the intermediate position shown in Figs. 1 and 6, and are tuned to substantially the fre quency of the alternating current supplied to the coils 26 and 27. The upper ends of the springs are secured to laterally spaced upright legs 45 of a cross tie or support 46 mounted in the upper end of the casing 12. This cross tie is mounted in a cup-shaped insert 47 mounted in an opening in the end of the housing or casing and secured therein by suitable screws 48 located in open ings in the housing and passing through the side frame supporting members 49 and the springs 39, and are threaded into the legs 45 of the cross tie. These screws therefore secure all these members together, the other ends 49a of the side frame members 49 being substantially U-shaped and embracing the upper end portions of the outer legs 18 of the magnetic core and secured thereto by any suitable means, such, for example, as the rivets 50. These side members and the springs, therefore, accurately locate the armature 25 with the poles 21 and 22 of the magnetic core.

The armature is connected with the tool 16 by a drive rod or pin 51. Any suitable holder may be provided for the tool 16, that shown being a split cup member 52 mounted on the outer end of the drive pin or rod 51. The other end 53 of this drive pin is rounded or spherical and seats in a similarly shaped socket in a pivot cup 54 seated in an opening in the connecting bar 38 of the armature and supported therein by a flange 55 at its upper end. The drive pin or rod 51 passes through a pivot pad or block 56 of semi-hard resilient material, such, for example, as rubber, forming a fulcrum for the drive pin, and the pin may be reduced at 57 so that this pivot or fulcrum pad will retain a given position on the rod. This pad is supported by the cross tie 46 between the upright legs 45 and against a connecting cross wall 58 having a notch or opening 59 through which the pin 51 passes. With this arrangement the pivot block or pad 56 is shiftable laterally on the wall 58 and is guided at its opposite ends between the legs 45 for a purpose presently to be described.

The cross tie member 46 is provided with a downwardly extending flange or cross wall 60 on which is mounted, and depending from it, a contact plate 61 of insulating material, which is secured to the wall 60 by any suitable means, such, for example, as the screws 62. This insulating plate forms a support and mounting for a pair of switch contacts 63 and 64. The outer or shorter contact 63 is mounted on a contact support secured to the plate 61 by any suitable means, such, for example,

as the rivets 66, and the contact 64 is mounted on a similar but shorter contact support 67 secured to the insulating plate 61 by any suitable means, such as the rivets 68. These two supports are spaced from each other and are therefore insulated from each other by the plate 61, and each support 65 and 67 is provided with a lug or car 69 and 70 respectively passing through the plate 61, and are connected with the lead wires 35 and 33 respectively of the exciter coils of the activator and thus form electrical connection from these coils to the switch contacts 63 and 64. The outer contact 63 is a flexible spring contact and may yield outwardly, while the inner contact 64 is a movable spring contact and is offset at its free end, as indicated at 71, to form a seat for one edge of the pivot or fulcrum block or pad 66. The spherical end 53 of the drive pin or rod 51 forms a pivotal drive connection between. the armature nd h pin and therefore the intermediate pivot block 56 is free to slide laterally in its support 46. The socket 54a in member 54 is flared outwardly at the top to permit universal rocking movement of pin 51 as the armature reciprocates or pivot block 56 is shifted. Member 56 is shown in the normal or inoperative position in Fig. 2, but if the tool 16 is pressed against the surface of the work, as, for example, in making an erasure on the right hand side as indicated by the arrow 72 in Fig. 2 and as shown in Fig. 3, the work surface being indicated at W, this tool will be forced to the left, carrying with it pivot block 56. This will move the upper end of the switch contact 64 to the left as shown in Fig. 1, bringing it into engagement with the end 73 of the outer contact 63, as shown in Fig. 3, thus closing the circuit through the coils of the activator. This will cause the activator to reciprocate the armature 25 and through the drive pin or rod 51 will reciprocate the tool 16 to perform the work desired, such, for example, as operating an eraser, burnisher, or other device. The spring contact 64 tends to shift the pivot block 56 in the opposite direction, and therefore as soon as pressure of the tool on the work surface is released contact 64 will shift the block 56 to the right to the position shown in Fig. 2 and will open the circuit to stop operation of the activator.

As the pin 51 may be turned or rotated about its longitudinal axis in the pivot block 56 and also its opposite end 53 is rotatable in the pivot or drive cup 54, this pin and with it the tool may be rotated, so that as one side wears down the opposite side may be brought into working position, and thus, if the tool is an eraser, for example, the V-shaped or tapered end, together with the sharp end edge 74 may be maintained for fine line erasing and better functioning of the tool.

The leads 15 from the opposite sides 30 and 32 of the source of current supply may be led into the casing through an opening in the opposite end from the tool and protected by any suitable grommet 75 of rubber or any suitable material. An end bracket 76 is mounted on the end of the laminated core by the rivets 24, this bracket including upright side flanges 77 located on opposite sides of the core, there being a pair of laterally spaced flanges at each side of the core and connected by an intermediate plate 78 on the lower side of which is mounted a terminal plate 79 of insulating material and secured to the bracket plate by any suitable means, such as the screw 80. Mounted on this insulating plate 79 is a pair of terminal clips 81 and 82 which may be of any suitable construction, but in the present case comprise metal tubes or sleeves each provided with an intermediate flange 83, and the tubular upper ends above the flange are passed through openings in the horizontal leg of an L-shaped terminal clip 84 and an opening in the plate 79 and are rolled or spun over on top of this plate, as shown at 85, to thus secure the terminal 81 and the clip 84 to the plate and in electrical contact with each other. The lead wires 15 are connected to these terminals in any suitable way, as, for example, compressing the opposite sides against the wire, as indicated at 86, or soldering, and the clips 84 are connected to the coils 26 and 27 by continuation of the leads 30 and 32.

With this device as illustrated, the motor functions and therefore the tube is operated only when pressed against the work, and the act of pressing the tool against the work automatically closes the circuit to cause the activator to function, and release of this pressure will permit the switch to automatically open and stop the activator. However, if desired, a hand button or similar device (not shown) could be mounted in the casing 12 outside of the contact 63 to press the free end of this contact against the contact 64 to close the circuit and control the motor by hand operation, or permit operation when the tool is not against the work.

The activator is mounted in the lower section 11 of the casing by means of a pair of screws 87 passing through openings in the lower end of thecasing, as shownin Fig. 1', and threaded into tapped .openingsiin the cross wall of the end bracket 76. As these screws are tightened up, they draw the whole motor assembly downwardly, and as the upper end of this assembly is connectedtothe upper section 12 of the casing by the screws 48,'tightening of these screws 87 will clamp the abutting ends of the casing sections together at the joint 13 and will retain the whole device in assembled relation.

Having thus set forth the nature of my invention, I claim:

1. In a device of the character described, an activator comprising a core including spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, means for magnetizing the poles to reciprocate the armature comprising a capacitat'ive winding of two coils wound together so that the corresponding turns of the coils are side by side, means connecting one end of one coil to the opposite end-of the other coil, a switch in said connection including cooperating contacts one of which is movable to and from the other, a potential absorbing winding between each coil and the switch, a drive pin connected with the armature, a fulcrum member for the pin mounted for lateral shifting movement by manual pressure on the pin, said movable switch contact being connected with said member for movement therewith toward and from the other contact to control operation of the armature, and means for connecting the other ends of the coils respectively to the opposite sides of a current supply.

2. In a device of the character described, an activator comprising a core including spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, a driving connection from the armature, means for magnetizing the poles to reciprocate the armature comprising a capacitative winding of two coils wound together so the corresponding turns of the coils are side by side, means connecting one end of one coil to the opposite end of the other coil, a control switch in said connection, an auxiliary coil of a few turns on the core between each coil and the switch, and means for connecting the other ends of the first coils respectively to the opposite sides of a current supply.

3. In a device of the character described, an activator comprising a core including spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, a driving connection from the armature, means for magnetizing the poles to reciprocate the armature comprising a capacitative winding of two coils wound together so the corresponding turns of the coils are side by side, means connecting the adjacent end of one coil to the remote end of the other coil, a control switch in said connection, a potential absorbing winding of a few turns in the connection between each coil and the switch, a connection from the remote end of the first coil to one side of a current supply, and a connection from the ad jacent end of the second coil to the other side of the current supply.

4. In a device of the character described, an activator comprising a core including spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, means for magnetizing the poles to re ciprocate the armature including a coil in an electric circuit, a switch for controlling said circuit including cooperating contacts one of which is movable to and from the other, a support, a pad of resilient yieldable material carried by said support, means securing the pad on the support against movement in the direction of movement of the armature while permitting movement in a direction at right angles thereto, a driving pin connected with the armature and extending through said pad so that the pad forms a fulcrum for the pin about which the pin is oscillated by movement of the armature, said pin and pad being shiftable by lateral manual pressure in a direction at right angles to the movement of the armature, and

6 said movable contact being connected with the pad so that shifting of the pad by said pressure will shift the movable contact relative to the other contact to control the circuit.

5. In a device of the character described, an activator including a movable driving member, means for operating said member including an electric circuit, a switch for controlling said circuit including cooperating contacts one of which is movable to and from the other,

asupport, a pad of yieldable resilient material carried by said support, means securing the pad on the support against movement in the direction of movement of the armature while permitting movement in a direction at right angles thereto, a driving pin connected with said driving member and extending through said pad so that the pad forms a. yieldable fulcrum for the .pin about which the pin is oscillated by movement of .the armature, said pin and pad being'shiftable :by'lateral manual pressure on the pin in a direction at right angles to the movement of the armature, and said movable contact being connected with the pad so that shifting .of the pad by said pressure will shift the movable contact relative to the other contact to control the circuit.

6. In a device of the character described, an activator including a movable driving member mounted to reciprocate in a given plane, means for operating said member including an electric circuit, a switch for controlling said circuit including cooperating contacts one of which is movable to and from the other, a driving pin connected with said driving member, means mounting the pin for limited shifting movement by lateral manual pres sure on the pin in a direction at light angles to the plane of movement of the driving member while said mounting means is held against movement in said plane, and means connecting said pin with the movable contact so that shifting of the pin by said pressure will shift said contact relative to the other contact to control the circuit.

7. The device of claim 6 in which the movable contact is a spring contact tending to shift the pin in the opposite direction from that in which it is shifted by said pressure.

8. In a device of the character described, an activator comprising a core including side by side laterally spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, means for magnetizing the poles to reciprocate the armature including a coil in an electric circuit, a switch for controlling said circuit including cooperating contacts one of which is movable to and from the other, a support, a driving pin connected with the armature, a fulcrum member for the pin mounted for lateral shifting movement on the support in a direction at right angles to the direction of movement of the armature while held against movement in the direction of movement of the armature, said fulcrum member forming a fulcrum for the pin about which it is oscillated by movement of the armature, and said movable contact being connected with said fulcrum memher, so that shifting of said member by manual pressure on the pin will shift the movable contact to control the circuit.

9. In a device of the character described, an activator comprising a core including spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, means for magnetizing the poles to reciprocate the armature including a coil in an electric circuit, a switch for controlling said circuit including cooperating contacts one of which is movable to and from the other, a support, an insulating plate mounted on and depending from said support, means mounting said contacts on the plate, a pad of resilient yieldable material carried by said support and shiftable thereon in a direction at right angles to the direction of movement of the armature while held against movement in the direction of movement of this armature, a driving pin connected with the armature and extending through said pad so it forms a fulcrum for the pin about which it is oscillated by movement of the armature, said pin and pad being shiftable in a direction at right angles to the plane of movement of the armature by lateral manual pressure, and said movable contact being connected with the pad so that shifting of the pad Will shift the movable contact to control the circuit.

10. In a device of the character described, a casing, an activator comprising a core including side by side laterally spaced magnetic poles, an armature closely adjacent the poles and movable transversely thereof, means for magnetizing the poles to reciprocate the armature including a coil in an electric circuit, a support mounted in one end of the casing, a switch for controlling the circuit comprising cooperating contacts mounted on said support one of which is movable to and from the other, a drive pin connected to the armature, a fulcrum member for the pin mounted on the support and shiftable laterally thereon in a direction at right angles to the plane of movement of the armature While held against movement a in this plane, said member forming a fulcrum for the pin about which it is oscillated by movement of the armature, means connecting the movable contact with the fulcrum member, said pin and fulcrum member being shiftable laterally by manual pressure on the pin at right angles to the plane of movement of the armature to shift the movable contact to control the circuit, a bracket on the core adjacent the other end of the casing, and screws extending longitudinally through the latter end of the casing and connected with said bracket to secure the activator in the casing.

References Cited in the file of this patent UNITED STATES PATENTS 1,232,174 Bachelet July 3, 1917 2,319,205 Buck May 18, 1943 2,343,237 McElroy et al Mar. 7, 1944 2,434,671 Murphy Jan. 20, 1948 2,513,577 Malme July 4, 1950 FOREIGN PATENTS 828,332 France Feb. 7, 1938 

